Cover fastenable on a container connection

ABSTRACT

The present invention relates to a rotatable cover which can be screwed or plugged on and is to be fastened on a stationary connection of a motor vehicle radiator or compensator reservoir of cooling and heating systems. The cover has a screw or plug cap and/or swivel cap and a rotatable engagement part in which a valve in the form of a combined overpressure/underpressure unit is arranged concentrically. The valve has a sealing member which produces a sealing connection with the stationary connection when the cover is applied. When the cover is positioned on the stationary connection, it is possible to prevent by means of a temperature-related control member removal, such as unscrewing or twisting of the cover. The temperature-related control member or a coupling part actuated by means of the temperature-related control member can be moved substantially radially between a coupling position and a release position. Consequently, a cover is produced which cannot be removed in cooling systems in which the temperature is still excessive, but which can be removed only when the excessive temperature has fallen completely, the cover nevertheless having a space-saving structure.

FIELD OF THE INVENTION

The present invention relates to a closure cover to be fastened,preferably by screwing on or slipping on and twisting, onto a stationaryconnection, for instance of a motor vehicle radiator, a compensationvessel in cooling or heating systems, or the like.

BACKGROUND OF THE INVENTION

Such closure covers are known from German patent DE 44 22 292 A1. Theyare used for instance in motor vehicle cooling systems, either directlyas a radiator cap or as a closure for the compensation vessel. Theclosure cover can either be screwed on by means of a thread or slippedon and twisted by means of a bayonet element. In motor vehicle coolingsystems, there is a problem with respect to the closure cover, which isthat as a rule, because of the high temperature in the cooling system,the pressure is also high.

Even if at the moment the engine is turned off the temperature in thecooling system is not overly high, still an increase in temperature andthus pressure can occur in the cooling system after engine shutoff froma certain residual heating effect. If the user then immediately removesthe closure cover of the cooling system, he runs an acute risk of beingburned. This risk exists particularly in screw-type closure covers,because on unscrewing the closure cover the user is not made to slowdown the unscrewing in the final phase or even better to interrupt it inorder to make a pressure equalization with the ambient air and above allto wait. When a closure cover is screwed onto the cooling system, it istrue that a venting connection to the outside is opened, but venting forpressure equalization cannot happen as fast as the user can possiblyunscrew the closure cover completely. The same is correspondingly truefor the use of a cover with a bayonet closure.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a novel structuralform, with which coupling in a manner fixed against rotation at normaltemperature and uncoupling at excess temperature can be reached equallyreliably as with the known closure cover, and which allows a noveldesign of the components that cooperate for coupling and uncoupling.

To attain this object, in a closure cover of the type defined at theoutset, the closure cover, in the state in which it is put on thestationary connection, can be secured against removal, preferably byunscrewing or untwisting, by means of a temperature-dependent controlelement, and the temperature-dependent control element a coupling part,is movable substantially approximately radially between a couplingposition and a release position.

By means of the provisions of the present invention, a closure cover iscreated which, whenever a critical high temperature still prevails inthe cooling system (or in the heating system) it cannot be removed.Injuries from high temperature and the resultant overpressure in thestationary connection when the closure cover is opened are thusprevented in every case. The temperature-dependent control element isaccommodated in a space-saving way together with the coupling element.

In accordance with one exemplary embodiment, it is possible for thetemperature-dependent element to be provided between the cap and thevalve, and the cap and the connection, so that the cap is locked in amanner fixed against relative rotation relative to the stationaryconnection.

A preferred embodiment of the present invention is realized inaccordance with the fact that the engagement part is held rotatablyrelative to the cap, and that with the said of the temperature-dependentcontrol element, a coupling, in a manner fixed against relativerotation, between the cap and the engagement part, is attainable atnormal temperature, and a decoupling between them is attainable atexcess temperature. As a result, in the event of an overtemperature, thecap turns uselessly relative to the engagement part, so that it is notpossible, even by force, to release the closure cover from thestationary connection.

Japanese patent, JP 62159721 discloses a twist-off prevention means withradially movable components. This closure cover, however, is not of thesame generic type as that of the present invention since it has noengagement part that is rotatable relative to the cap. The same is trueof German patent, DE 38 28 462 A1.

Further details of the present invention can be learned from the ensuingdescription, in which the present invention is described and explainedin further detail in terms of the exemplary embodiments shown in thedrawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section through a closure cover, in accordance with anexemplary embodiment of the present invention, screwed onto a stationaryconnection of a container, with a temperature-dependent twist-offprevention means according to the present invention, and

FIG. 2. is a cross-sectional view, corresponding to FIG. 1, of a furtherembodiment of the closure cover of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The closure cover 10 shown in the drawing is screwed onto a stationaryconnection 11 of a compensation vessel 12, c-20 shown in onlyfragmentary form, of a motor vehicle cooling system. The closure cover10 includes a screw-type cap 14, an engagement part 16 that has a malethread 18 with which the closure cover 10 can be screwed into a femalethread 20 of the connection 11, and a valve 22. In the instance shown,the connection 11 of the compensation vessel 12 has two concentricparts, namely on the outside a female thread part 23 carrying the femalethread 20, and an inner neck region 24, which is engaged on the insideby the valve 22 of the closure cover 10. It is understood that it isalso possible to provide the closure cover 10 with a female threadand/or to embody it in such a way that it can be screwed directly on tothe stationary connection of a motor vehicle radiator.

The closure cover 10 of the present invention has atemperature-dependent twist-off prevention means 26, which assures thatthe closure cover 10 cannot be released or unscrewed from the stationaryconnection 11 until the compensation vessel 12, vehicle radiator, or thelike, has dropped to normal or ambient temperature.

The cap 14 of the closure cover 10 forms a cup-shaped void 28, whichopens in caplike fashion toward the bottom when the closure cover 10 isdisposed on a horizontal opening. The void 28 is closed by theengagement part 16, which is held on the cap 14 such that it can berotated in the circumferential direction relative to the cap 14 but isimmovable in the axial direction. The component called the engagementpart 16 can, in another embodiment, be embodied to fit over a protrudinghousing connection and may correspondingly have a female thread, andthus the term engagement part must not be understood in a limiting way.

Inside the engagement part 16, a valve housing 30 of the valve 22 isrotatable relative to the cap 14 and is held substantially immovably inthe axial direction. The valve 22 is embodied in a manner known per seas a combined overpressure/underpressure valve, which opens if anexcessive overpressure or underpressure occurs while the closure cover10 is screwed onto the stationary neck 11 and thus protects the coolingsystem. The valve housing 30, on a front portion 32, is provided with anannular groove 34, in which an 0 ring 36 is laid that rests sealingly,when the closure cover 10 is screwed on, on the smooth inside face 38 ofthe neck 24 of the compensation vessel 12.

The twist-off prevention means 26 includes a temperature-dependentcontrol element 40, which extends substantially axially and is retainedon its lower end 42 on the engagement part 16. The control element 40can be deflected essentially radially. In the region of its upper end44, it cooperates with a concentric wall region 46, defining a couplingpart of the cap 14 that protrudes from above into the void 28 from theinner wall of the cap. The wall region defines teeth 50 in which one endof the control element 40 engages. The control element 40, in a couplingposition, is connected in a manner fixed against relative rotation tothe concentric wall region 46 in one of the teeth 50 and thus to thescrew-type cap 14. Deflection of the control element 40 substantiallyradially puts the control element into a release position relative tothe cap 14, so that the cap 14 is rotatable relative to the engagementpart 16, with the consequence that the closure cover 10 cannot beunscrewed from the connection 11; at overtemperature, it turnsuselessly.

The control element 40 may preferably be a bimetallic strip 48. Thecontrol element 40 or bimetallic strip could also be joined to acoupling part, not shown in the drawing, such as a pin or the like thatthen cooperates in a coupling or noncoupling fashion with the cap 14(or, in other embodiments, with the connection, the valve, or theengagement part).

In the region of its upper end 44, the control element 40 can cooperateby means of a toothed ratchet connection 50 with the concentric wallregion 46, so that the control element 40 in its release position, canslide past the toothed outer face of the concentric wall region 46,which means that a rotary motion of the screw-type cap 14 cannot betransmitted to the engagement part 16, and therefore the closure cover10 cannot be unscrewed from the connection 11.

The control element 40 is shown in FIG. 1 as a bimetallic strip 48 inits two positions. In the coupling position, represented by dashedlines, at the normal temperature of the control element 40, a connectionfixed against relative rotation is made between the cap 14 and theengagement part 16, and the screw-type lid 10 can therefore be unscrewedfrom the container connection 11. If an excess temperature prevails inthe interior of the compensation vessel 12, then the bimetallic strip 48is deflected radially outward and brought into its release positionshown, on the left in the drawing, in which a rotation of the cap 14 isnot transmitted to the insert part 16 and thus the cap 14 turnsuselessly, and the closure cover 10 can accordingly not be unscrewed.

Instead of using the bimetallic strip 48, a memory spring could also beused, which cooperates with a radially movable and in particular pinlikecoupling part in such a manner that the coupling part, upon acorresponding change in the memory spring, can be shifted radially intoa coupling position or into a release position.

FIG. 2 shows one embodiment of a closure cover 60 that can be screwed toa connection, not shown. The closure cover 60 includes a screw-type cap62 and an engagement part 64, which is either fixed against relativerotation or is rotatable relative to the screw-type cap 62, and whichhas a flangelike threaded portion 66 with which the closure cover 60 canbe screwed to a threaded connection. As in the exemplary embodiment ofFIG. 1, a centrally disposed valve unit 68 is disposed inside theengagement part 64; this valve unit is extensively equivalent to thevalve unit 22 described in conjunction with FIG. 1 and thereforerequires no further explanation here.

The engagement part 64 includes a temperature-dependent control element70, including a memory spring 72. The memory spring 72 is disposed on aradially displacable, pinlike coupling part 74 and is received with itin a radially offset bore 76 in the engagement wart 64. It is supportedon one end on an annular collar 78 of the pinlike coupling part 74 andon the other end on a radial closure part 80, which closes off theoffset bore 76 from the outside and has a radial opening 82 that ispenetrated by the pinlike coupling part 74. On the other side of theannular collar 78, a further spring 84 is provided on the pinlikecoupling part 74. It is braced on one end against the annular collar 78and on the other against the radially inner collar of the offset bore76. The spring 84 thus exerts prestressing on the pinlike couplingelement 74 and seeks to urge it radially outward, counter to the springforce of the memory spring 72. The radially outer end 86 of the pinlikecoupling part 74 is moved, at normal temperature of the memory spring 72and spring 84, into the coupling position shown in FIG. 2. In thisposition, the end 86 engages a detent bore 88 in the screw-type cap 62and thus assures a coupling, in a manner fixed against relativerotation, between the screw-type cap 62 and the engagement part 64, sothat the closure cover 60 can be screwed on and unscrewed. In the eventof excess temperature, the memory spring 72 stretches, and the pinlikecoupling part 74 is urged radially inward, so that the end 86 comes freeof the detent bore 88 and the screw-type cap 62 turns uselessly relativeto the engagement part. Unscrewing of the closure cover 60 is thenimpossible.

It should also be noted at this point that embodiments are conceivablein which the component designated as an engagement insert part isdisposed in a manner fixed against relative rotation with respect to thecap 14, 62; in that case, the temperature-dependent twist-off preventionmeans is embodied such that when a certain excess temperature isreached, the cap 14, 62 is locked in a manner fixed against relativerotation with respect to the container or the container connection.

What is claimed is:
 1. A closure cover for fastening on a stationaryconnection of a compensating vessel of a cooling or heating system,comprising: a cap which can be connected to the stationary connectionaccording to one of: being screwed on, being insertably slipped on, andbeing twisting on the stationary connection; a rotatable engagement partconnected to said cap; an overpressure/underpressure valve arrangedconcentrically with said cap and said rotatable engagement part, saidvalve having a sealing element which sealingly engages the stationaryconnection when said cap is connected to the stationary connection; anda temperature-dependent control element mounted to said rotatableengagement part, said control element being movable substantiallyapproximately radially relative to said cap between a coupling positionand a release position, in said release position said control elementpreventing removal of said cap from the stationary connection by one ofscrewing, slipping and twisting, and in the latter position said controlelement permitting removal of said cap from the stationary connection byone of: screwing, slipping and twisting.
 2. The closure cover as definedin claim 1, wherein said cap includes a coupling part which is engagedby said control element at said coupling position.
 3. The closure coveras defined in claim 1, wherein said control element when in saidcoupling position prevents relative rotation of said cap and said valvewhen a normal temperature exists in the compensating vessel, and when anexcess temperature exists in the compensating vessel said controlelement reaches said release position thereby permitting relativerotation of said cap and said valve so that the closure cover cannot beremoved from the stationary connection.
 4. The closure cover as definedin claim 1, wherein said control element when in said coupling positionprevents relative rotation of said cap and said engagement part when anormal temperature exists in the compensating vessel, and when an excesstemperature exists in the compensating vessel said control elementreaches said release position thereby permitting relative rotation ofsaid cap and said engagement part so that the closure cover cannot beremoved from the stationary connection.
 5. The closure cover as definedin claim 1, wherein said engagement part forms one piece with said cap,and wherein at an excess temperature in the compensating vessel saidcontrol element reaches said release position thereby permittingrelative rotation of said engagement part relative to the stationaryconnection.
 6. The closure cover as defined in claim 1, wherein saidcontrol element is formed by a bimetallic strip.
 7. The closure cover asdefined in claim 1, wherein said control element is formed by a memoryspring.
 8. The closure cover as defined in claim 1, wherein said controlelement includes a coupling part which is one of: a striplike, aplatelike, and a pinlike coupling part, said coupling part beingretained fixed against rotation in the circumferential direction of saidcover, and movable or deflectable in the radial direction, and whereinsaid coupling part being movable between a coupling position and arelease position with said control element.
 9. The closure cover asdefined in claim 1, wherein said cap defines a counterpart face forminga coupling part, and wherein said control element is formed by abimetallic strip, one end of which is fastened to said engagement part,and the other end of which is radially deflectable and cooperates withsaid counterpart face on said cap.
 10. The closure cover as defined inclaim 2, wherein said coupling part includes teeth for effecting therotationally fixed coupling of said cap and said engagement part andsaid cap and said valve.